EPA/Claudio ReyesPicture of equipment used for drilling at the San Jose mine, in Copiapo, Chile, 23 August 2010, where 33 workers have been trapped, deep underground, for more than 15 days. Rescue efforts are continuing after a note reading, 'All 33 of us are fine in the shelter' was received on 22 August through a small hole drilled by rescuers.

Martin Bernetti/AFP/Getty ImagesPicture of a banner with the pictures of the 33 miners trapped in the mine.

COPIAPO, Chile — Each of the 33 miners trapped a half-mile underground lived on two spoonfuls of tuna, a sip of milk and a bite of crackers. Every other day.

They were so careful in eating what was supposed to be a two-day emergency supply that when the outside world finally reached them 17 days after a mine collapse, they still had some food left.

"We heard them with such strength, such spirit, which is a reflection of what for them has been a gigantic fortitude and a very well organized effort," Mining Minister Laurence Golborne said today after talking with the miners at length the night before through an intercom system lowered into their underground refuge. "The way that they have rationed the food, just as they've performed throughout this crisis, is an example for all of us."

The miners were plunged into darkness by the Aug. 5 collapse of the main shaft of a gold and silver mine that runs like a corkscrew for miles under a barren mountain in northern Chile's Atacama desert. They gained contact with the outside world Sunday when rescuers drilled down to their living room-sized shelter after several failed attempts.

The miners said they have honored the same hierarchy they used on any work shift, following the directions of 54-year-old shift foreman Luis Urzua.

They conserved the use of their helmet lamps, their only source of light other than a handful of vehicles whose engines contaminate the air supply. They fired up a bulldozer to carve into a natural water deposit, but otherwise minimized using the vehicles that contaminate the available air.

The miners can still reach many chambers and access ramps in the lower reaches of the mine, and have used a separate chamber some distance from their reinforced emergency chamber as their bathroom. But they have mostly stayed in the shelter, where they knew rescuers would try to reach them.

The room has become stiflingly hot and stuffy. Leaving it allows them to breathe better air, but wandering too far is risky in the unstable mine, which has suffered several rock collapses since the initial accident.

Rescue efforts advanced considerably today as a third bore-hole prepared to break through to the miners, and a huge machine arrived from central Chile to carve out a tunnel just wide enough for the miners to be pulled out one-by-one. That machine won't begin drilling for several days, however, and engineers are so concerned about preventing another collapse that they plan on taking up to four months to reach the men.

"It's been like a heart that's breaking, but we're thankful they're all alive," bore-hole driller Rodrigo Carreno told The Associated Press as he prepared to leave today. "We did everything we could to save them, and in the end we succeeded."

The three 6-inch-wide (15-centimeter) shafts will serve as the miners' "umbilical cords" in the long weeks ahead — one for supplies, another for communications and a third to guarantee their air supply.

A steady flow of emergency supplies was sent down to the miners on today in a rocket-shaped metal tube called a "paloma," Spanish for dove. The paloma is 5 1/4 feet (1.6 meters) long and takes a full hour to descend through the bore-hole.

The supplies included 33 small low-intensity and low-energy LED lights, so that each miner can have a light source that won't bother his eyes in the otherwise murky depths of the mine. Also sent down today was "more nutritive food" in the form of a vitamin-enriched gel, along with eye patches, aspirin and medicine for one miner who has diabetes and another who suffers from the respiratory disease silicosis, Health Minister Jaime Manalich said today.

Family members who have maintained an anxious vigil outside the mine were encouraged to send notes down today. First was Lila Ramirez, answering the "Dear Lila" letter from her husband, Mario Gomez, that thrilled the nation when President Sebastian Pinera read it aloud, providing the first details of the miners' survival.

"I wrote him just now and told him to be very patient, that we're all camped out here, following his every heartbeat. That he shouldn't become desperate, and that he try to be extremely tranquil," Ramirez told the AP.

She said her husband, the eldest of the miners at 63, has likely helped the shift foreman Urzua keep the other men feeling positive.

"For my husband, it's not necessary that they ask him to step up — he was born to be a leader. I think it's him that is managing the situation," she said.

With each passing day, the families have been praying for their trapped husbands, fathers, brothers and boyfriends in tents surrounding the mine entrance, high on a barren mountain where cold nights end in a chilly fog. There's a bonfire to keep warm, and barbecue and other food donated by the local government in a common tent.

"We're not going to abandon this camp until we go out with the last miner left," said Maria Segovia. "There are 33 of them, and one is my brother."

Before the miners were discovered alive on Sunday, many Chileans were beginning to assume the worst. The stunning news of their survival prompted euphoria and pride across a country still recovering from one of the world's most powerful earthquakes.

Urzua assured Golborne, the mining minister, that they were all doing well, and asked whether their fellow miners working above them managed to escape the Aug. 5 collapse. Golborne said all were safe, prompting cheers from the miners below. Moments later, the miners joined in a cheer and sang the national anthem in a full-throated chorus, prompting more cheers, applause and tears among the crowd above.

In one more week, the men will have been trapped underground longer than any other miners in history. Last year, three miners survived 25 days trapped in a flooded mine in southern China. Few other rescues have taken more than two weeks.

Chile is the world's top copper producer and a leading gold producer, and has some of the world's most advanced mining operations.

The mine where the miners are trapped was closed in 2007 after an explosion killed three workers, but was allowed to reopen the next year — without security improvements, miners' families and union co-workers say. The allegations prompted Pinera to fire the three leading mine safety regulators involved, and to promise no impunity should criminal liability be discovered.

Golborne said that if a ventilation shaft had been in good condition, the miners would have been able to use it to escape. Urzua told the minister that they had tried, but the route was blocked.